Question

When a 4 V battery is connected across an unknown resistor there is a current
of 100 mA in the circuit. The value of the resistance of the resistor is:
(a) 4Ω
(b) 40 Ω
(c) 400 Ω
(d) 0.4Ω​

Answer 1

Answer:

(ii.) 40ohm

Explanation:

40 Ω. V=IR,  V = 4V, I = 100 mA = 0.1 A 

Hence R = V/I = 4/0.1 Ω = 40 Ω

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Answer 2

Resistance of resistor is 40Ω

Solution

Given that when a 4 V battery is connected across an unknown resistor there is a current

of 100 mA in the circuit.

We have to find the value of the resistance of the resistor is:

(a) 4Ω

(b) 40 Ω

(c) 400 Ω

(d) 0.4Ω

Here we have ;

→ Potential difference (V) = 4v

→ Current flowing (I) = 100 mA

= (100/1000) A

= 0.1 A

Now as we know Ohm's law :-

→ V = I * R

Where,

• V denotes potential difference
• I denotes current flowing
• R denotes resistance

Substituting values,

→ 4 = 0.1 * R

→ 4 = 0.1R

→ R = 4/0.1

→ R = 40Ω

Hence,

Resistance of resistor = b)40Ω